1. Field of the Invention
The present invention relates to an internal combustion engine fuel injection timing control system which is designed to control the fuel injection timing of an injection pump employed in a fuel injection system of the type incorporated in an internal combustion engine, particularly a Diesel engine, in accordance with electrically detected operating parameter signals.
2. Description of the Prior Art
In the past, as a means for controlling the fuel injection timing of an injection pump, such as an in-line injection pump used in a Diesel engine, a mechanical injection advance system known as the "automatic timer" has been employed.
This system is so designed that the driving shaft of an injection pump is advanced by the centrifugal force generated by the weights which rotate along with the driving shaft of the injection pump. Therefore, while this system is capable of performing a simple injection timing control of such a kind as advancing the injection timing in proportion to the rotational speed of the engine, it is essential for the purpose of engine exhaust emission control and noise suppression that not only the rotational speed of an engine, but also other operating parameters, in particular the amount of fuel injected into the engine from an injection pump be reflected properly in the fuel injection timing.
There is thus a problem that the fuel injection timing control characteristic which meets these requirements cannot readily be provided by the conventional mechanical injection advance systems utilizing only the centrifugal force.